This disclosure relates generally to online systems, and in particular to measuring deletion of cookies by users of an online system.
An online system allows its users to connect to and communicate with other online system users. Users may create profiles on an online system that are tied to their identities and include information about the users, such as interests and demographic information. The users may be individuals or entities such as corporations or charities. Because of the increasing popularity of online systems and the increasing amount of user-specific information maintained by online systems, an online system provides an ideal forum for advertisers to increase awareness about products or services by presenting advertisements to online system users. For example, presenting advertisements to users of an online system allows an advertiser to persuade online system users to take an action regarding the advertiser's products or services. Many online systems generate revenue by charging advertisers for each presentation of an advertisement to an online system user (e.g., each “impression” of the advertisement) or interaction with an advertisement by an online system user.
Effectiveness of advertising campaigns conducted on an online system may be improved by storing cookies on a device and/or browser used to access the online system. These cookies enable advertisers to store and retrieve information describing a user associated with the device or browser. For example, a cookie allows an advertiser to determine a user's preferred websites and the user's browsing activity (e.g., information describing the user logging into the online system, describing the user's interactions with advertisements and online content) over a variable time-frame. Cookies may also allow a user to store information describing the user in a cookie associated with a website for subsequent retrieval when the user accesses the website. Content providers may also use cookies to generate browsing histories for various users that may be used to by a content provider to target the user with advertisements for specific products or services.
However, users may delete cookies stored by a browser to clear their browsing histories, to reclaim storage space on a device, and/or to protect their privacy. Users may delete all cookies stored by a browser or may delete cookies associated with by particular websites. When a user deletes cookies, content providers are unable to ensure that the proper content is presented to a particular user.